My broad research area involves the variability and dynamics of marine food webs and ecosystems under global change. Locally, my research focus is on the productive marine ecosystems of the west and south coasts of southern Africa (the Benguela ecosystem), although I have also worked on projects in the more oligotrophic east coast region. As an ecosystem researcher, my work spans taxa from microbes to top predators, focusing on ecosystem responses to global change. My main research tools are ecological models for understanding complex interactions and feedbacks among physical, chemical and biological processes on many time and space scales. Current research is on "end-to-end" dynamics of eastern boundary upwelling ecosystems, involving field and modelling studies and with a focus on microbial dynamics.